Problem: $(-87+i)+(-5+20i)=$ Express your answer in the form $(a+bi)$.
Answer: Background Complex numbers can be added or subtracted by separately adding or subtracting their real and imaginary terms. To add or subtract complex numbers: Expand parentheses (attending to minus signs outside of parentheses if necessary) Combine all real terms (terms that do not contain $i$ ), and add or subtract them. Combine all imaginary terms (terms that contain $i$ ), and add or subtract them. Combining Like Terms $\begin{aligned} ({-87}+i)+({-5}+{20}i)&={-87}+i{-5}+{20}i \\\\ &={-87}{-5}+i+{20}i \\\\ &={-92}+{21}i \end{aligned}$ Summary $({-87}+i)+({-5}+{20}i)={-92}+{21}i$